Cutting and mulching equipment is often used to cut away and/or clear vegetation such as tall grass, plants, weeds, shrubs, small trees, branches, and the like. A rotary brush cutter is one such device commonly used for clearing brush. Such a cutter has a blade that rotates in a plane generally parallel to the ground to cut brush at a more or less uniform height. The blade is enclosed in a housing that rolls on wheels or slides along the ground during operation.A brush cutter is typically mounted on the front of a tractor or skid loader (trade name: Bobcat) or other such carrier or support device or equipment. During operation, the brush cutter clears a path for the operator and the support device on which the brush cutter is mounted. These support devices usually have hydraulically operated arms extending to the front to which the brush cutter attaches and which can lift the brush cutter from the ground during transport, and lower the brush cutter to the ground during use.
A rotary brush cutter may pose a risk of injury to an operator. A common problem occurs where the rotating blade strikes and throws an object from the cutting area of the blade. The object may for example, be a twig, a rock, or any other object that may pose a risk to an operator. Injury can occur should such a thrown object hit an operator or bystander.
The danger increases when the brush cutter is lifted from the ground, say for transport, servicing, or cleaning. The blade is easily accessible when the cutter is lifted. If the cutter is still spinning, the blade poses an obvious danger to those nearby.
It is thus preferable that the brush cutter have a safety mechanism, such as an automatic blade shut-down mechanism, for when the brush cutter is raised above the ground.
One mechanism in the prior art involves a set of rollers positioned at a rear portion of a brush cutter. These rollers are heavy so that they maintain contact with the ground. If the brush cutter is lifted above a predetermined height, the rollers drop down with respect to the brush cutter housing and actuate the automatic shut-off mechanism. A problem with this apparatus is that the rollers may cause an unnecessary shut-off if the brush cutter travels over a hole or crevice area that causes the rollers to drop down to the predetermined shut-off distance.
A similar problem can occur when the brush cutter travels over a log. The rollers will drop down once they have rolled over the log, thus unnecessarily implementing operation of the shut-off mechanism.
Another problem with this mechanism is that it adds significant weight to the brush cutter, thus limiting the vast majority of cabs that can carry the weight of the shut-off mechanism.
Another mechanism in the prior art involves the use of an apparatus wherein a shut-off mechanism is initiated based on the difference between the height of the brush cutter with respect to the height of a cab. This apparatus includes a chain having a first end bolted to the brush cutter and a second end secured to a chassis of the cab, to thus limit the height to which the brush cutter can be lifted off of the ground with respect to the cab. A problem with this mechanism is that the brush cutter may be located over an inclined surface with respect to the cab, thus unnecessarily initiating the shut-off mechanism.
Another problem with these prior art mechanisms is that they lack shut-off devices that extend along the entire length of the side of the brush cutter to prevent debris from escaping through the sides of the brush cutter. Also, these mechanisms can become caught on the ground and other debris during operation, requiring the operator to shut down the machine and clean them off. Another problem with these mechanisms is that they are independent of the electrical mechanism, or motor, that runs the brush cutter. Thus, the safety mechanisms may be removed from the brush cutter without affecting operation. For example, the chain or rollers may be removed from the brush cutter and the brush cutter will still be able to operate, thus making the effectiveness of the safety mechanism moot.
The present invention provides for an improved brush cutter that addresses these shortcomings.